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NTA Abhyas JEE Main2020PhysicsNuclear PhysicsPractice

Two radioactive materials X 1 and X 2 have decay constants 10 λ and λ respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of X 1 to that of X 2 will be 1 / e after time

Options

  1. A1 10 λ
  2. B1 11 λ
  3. C11 10 λ
  4. D1 9 λ

Correct answer

D. 1 9 λ

Step-by-step solution

N 1 = N 0 e − 10 λ t and N 2 = N 0 e − λ t N 1 N 2 = e - 1 0 λ t e - λ t = 1 e (given) ⇒ t = 1 9 λ

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